Arc is a member of the Imperial Guard, a multi-ethnic group of super-powered alien beings who act as enforcers of the laws of the Shi'ar Empire. Part of the division of the Imperial Guard known as the Superguardians, Arc spearheaded the Guard's first strike on the team of superhumanmutant adventurers known as the X-Men after his Empress Lilandra, under the mental control of Charles Xavier's mutant twin sister Cassandra Nova, had ordered the destruction of all mutants on Earth. Arc's squad captured two of the X-Men, the optic-blasting Cyclops and the helmeted healer Xorn, and took them to the orbiting Shi'ar superdestroyer to await execution. Arc was subsequently defeated by the X-Man the Beast.